The Lake Tapps problems is a series of very complicated issues. But very simply, it’s about water and who is entitled to it.
We must support fish and their environment. There is a disagreement on how far we have to go to provide adequate habitat for them. The people who live in the South King County and North Pierce County areas have very strong sentiments about maintaining minimum recreational levels at Lake Tapps during May through September.
The city wells, which supply the water for thousands of homes in the area, are very dependent on the underground water supply (aquifer), which Lake Tapps is a part of.
There is a warming trend, which over the next several years, significantly will affect the water-flow rate in the White River.
All of these issues must be considered when the final decisions on the Lake Tapps water right permit are made. The Washington State Environmental Department is the organization that presently is passing judgement on these issues.
Lake Tapps originally was four lakes (in 1909), which were combined into one lake by diverting water from the White River (Buckley) and building dikes in the areas around the lake to contain the additional water. The original four lakes were “fed” by a few underwater and underground streams.
Shortly after the generators at the Lake Tapps Power Station were shut down, it became easier to measure the amount of water coming into or going out of the lake, which is not accounted for by in-stream gauge instruments. In 2004 and 2005, daily measurements at the inlet and outlet were recorded. The data is available on the Internet.
After making the appropriate adjustments for known losses and analyzing the data, there are some interesting results.
During spring and early summer, the data shows there is an inflow of water over and above that is flowing in the inlet channel. In July, August and September, the data shows a large outflow of water, which is not going out at any visible outlet. The maximum outlet flows are the equivalent of what occurs in a small river.
During the time when Puget Sound Energy lowered the lake to extremely low levels to rework the lake dikes, many wells in the area went dry. This data is indicating that Lake Tapps presently is serving as a reservoir for the wells that are drawing from the underground aquifer in the Lake Tapps area. The cities of Auburn, Sumner and Bonney Lake all have wells that draw water from that aquifer.
The Lake Tapps math models, which has been created by various consultants and individuals, all have used an annual average for the lake loss that is an order of magnitude lower than those monthly averages derived from the 2004 and 2005 data (65 vs. a maximum of 600 cubic feet per second). Substituting amonthly lake loss, derived from ’04 and ’05 data for the annual lake loss used in the math models, would show results of very early loss of acceptable recreational lake levels almost each year.
Upon review of the White River flow data (recorded on a gauge located above the diversion dam), it shows very high water flow rates during spring and early summer. But in July, the river flow rates drop to 1,000 cubic feet per second (cfs) or less and in August, there are many days the rate drops below 800 cfs. If you subtract from those flow rates: 500 cfs for the fish in the White River bypass; 100 cfs for gauge and valve tolerances; 30 cfs for the fish screen return to the river; 150 cfs for the water right to the Cascade Water Alliance (Bellevue and surrounding cities), and then another 100-400 cfs for lake loss, you quickly run out of water. The lake level is doing to go down many times in July and almost every August. Also, there might be quite a few city wells that will do dry.
Plotting the average August flow rate for the White River over a 50-year period – and drawing an average line through those years of data – will show a drop in water flow rate in the White River of approximately 100 cubic feet per second. The warming trend and its effect on the White River must be considered.
Hopefully, our people in the State Department of Ecology are smart enough to realize all these facts and will provide a compromise solution that will accommodate these issues in the water right permit. If they reject the water right, then it appears the cities of Auburn, Sumner and Bonney Lake are prepared to buy Lake Tapps and its supporting elements.
The cities have committed to maintaining the lake levels during the summer recreational months; whereas, the CWA has offered PSE many millions of dollars to assist them in backing away from any agreements between the homeowners and those who own Lake Tapps (PSE or CWA).
Now is the time to express our concerns to the governor and state ecology officials.
Kan Castile is a Lake Tapps